Reward-related midbrain dopamine guides animal behavior, creating automatic approach towards objects associated with reward and avoidance from objects unlikely to be beneficial. Using measures of behavior and brain electricity we show that the dopamine system implements a similar principle in the deployment of covert attention in humans. Participants attend to an object associated with monetary reward and ignore an object associated with sub-optimal outcome, and do so even when they know this will result in bad task performance. The strength of reward's impact on attention is predicted by the neural response to reward feedback in anterior cingulate cortex, a brain area known to be a part of the dopamine reinforcement circuit. These results demonstrate a direct, non-volitional role for reinforcement learning in human attentional control.